diff --git a/doc/libcdio.texi b/doc/libcdio.texi index 4564e1d5..5e0e39b1 100644 --- a/doc/libcdio.texi +++ b/doc/libcdio.texi @@ -31,7 +31,7 @@ development.'' @titlepage @title GNU libcdio library -@subtitle $Id: libcdio.texi,v 1.1 2003/07/28 02:25:37 rocky Exp $ +@subtitle $Id: libcdio.texi,v 1.2 2003/07/28 10:46:24 rocky Exp $ @author Rocky Bernstein et al. @page @@ -199,41 +199,26 @@ The CD-ROM specification or "Yellow Book" followed a few years later and describes the extension of CD's to store computer data, i.e. CD-ROM (Compact Disk Read Only Memory). -The Yellow book CD standard defines two modes: +The Yellow book CD standard defines two modes: Mode1 and Mode1. -@subsection Mode1 - Mode 1 is the data storage mode used by to store computer - data. The data is laid out in basically the same way as in and audio - CD format, except that the 2,352 bytes of data in each block are - broken down further. 2,048 of these bytes are for "real" data. The - other 304 bytes are used for an additional level of error detecting - and correcting code. This is necessary because data CDs cannot - tolerate the loss of a handful of bits now and then, the way audio - CDs can. - -@subsection Mode2 - Mode 2 data CDs are the same as mode 1 CDs except that the error - detecting and correcting codes are omitted. This is similar to audio - CDs, i.e. the mode 2 format provides a more flexible vehicle for - storing types of data that do not require high data integrity: for - example, graphics and video can use this format. But in contrast to - the Red book standard, different modes can be mixed together; this is - the basis for the extensions to the original data CD standards known - as CD-ROM Extended Architecture, or CD-ROM XA. CD-ROM XA formats - currently in use are CD-I Bridge formats, Photo CD and VideoCD plus - Sony's Playstation. +@menu +* Mode1:: Mode 1 Format +* Mode2:: Mode 2 Format +@end menu @subsection ISO-9660 The Yellow Book does not actually specify how data is to be stored on or retrieved from a CD-ROM. It was feared that many different companies would implement proprietary data storage formats using this specification, resulting in many different incompatible data CDs. To -try to prevent this, representatives of major manufacturers met at the -High Sierra Hotel and Casino in Lake Tahoe, NV, in 1985, to come -together on a common standard for data CDs. This format was nicknamed -High Sierra Format. It was later modified slightly and adopted as ISO -standard 9660. ISO 9660 consists of several "levels": +prevent this, representatives of major manufacturers met at the High +Sierra Hotel and Casino in Lake Tahoe, NV, in 1985, to define a +standard for storing data on CDs. This format was nicknamed High +Sierra Format. In a slightly modified form it was later adopted as ISO +the ISO 9660 standard. This standard is further broken down into +3 "levels", the higher the level, the more permissive. +@subsubsection Level1 Level 1 ISO 9660 defines names in the 8+3 convention so familiar to MS-DOS: eight characters for the filename, a period, and then three characters for the file type, all in upper case. The @@ -242,9 +227,11 @@ requires that files occupy a contiguous range of sectors. This allows a file to be specified with a start block and a count. The maximum directory depth is 8. +@subsubsection Level2 Level 2 ISO 9660 allows far more flexibility in filenames, but isn't usable on some systems, notably MS-DOS. +@subsubsection Level3 Level 3 ISO-9660 allows non-contiguous files, useful if the file was written in multiple packets with packet-writing software. @@ -258,6 +245,30 @@ Another extension is the Rock Ridge Interchange Protocol (RRIP), which enables the recording of sufficient information to support POSIX File System semantics. +@node Mode1 +@subsection Mode1 +Mode 1 is the data storage mode used by to store computer +data. The data is laid out in basically the same way as in and audio +CD format, except that the 2,352 bytes of data in each block are +broken down further. 2,048 of these bytes are for "real" data. The +other 304 bytes are used for an additional level of error detecting +and correcting code. This is necessary because data CDs cannot +tolerate the loss of a handful of bits now and then, the way audio +CDs can. + +@node Mode2 +@subsection Mode2 +Mode 2 data CDs are the same as mode 1 CDs except that the error +detecting and correcting codes are omitted. This is similar to audio +CDs, i.e. the mode 2 format provides a more flexible vehicle for +storing types of data that do not require high data integrity: for +example, graphics and video can use this format. But in contrast to +the Red book standard, different modes can be mixed together; this is +the basis for the extensions to the original data CD standards known +as CD-ROM Extended Architecture, or CD-ROM XA. CD-ROM XA formats +currently in use are CD-I Bridge formats, Photo CD and VideoCD plus +Sony's Playstation. + @node White Book @section White Book The White Book, finalized in 1993, defines the VideoCD specification